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Dromaeosaur questions (long, I think)



Dear DMLs,

I can confirm now that here in Uruguay we have teeth from a Late
Jurassic-Early Cretaceous dromaeosaur (and a big one, height = 28 mm.). The
teeth, besides bieng laterally compresed and apically recurved, shares a lot
of characters with those from _Dromaeosaurus albertensis_ including low
DSDI, torsionated anterior carina, chisel-shaped denticles...
It cannot be a convergence. I know that there are some teeth worlwide that
have this features too, which can be included (I suppose) in the
Dromaeosaurinae. But I have a few questions:

1) How distinctive is the twisted anterior carina?  Although Currie (1990,
1994, 1995) says it is diagnostic for _D. albertensis_, it appears other
non-avian theropods shares this feature too: some _Saurnornitholestes_
teeth, tyrannosaurids (Sankey et al., 2002), _Acrocanthosaurus_ and
allosaurids (Currie & Carpenter, 2000) and even all carnosaurs (Feduccia,
2002, thanks Mickey!). It seems to me it doesn't have any diagnostic value
by itself. What do you think?

2) Has this twist any functional implication (when biting, blood flow or
something)?

3) Do you know any other dromaeosaurid from South America (or even Gondwana)
from Late Jurassic-Early Cretaceous times? I think there aren't (of course
there are possible dromaeosaurs from Late Cretaceous of Sudan, Brazil,
Argentina, Madagascar), so, due to biogeographical and chronological
reasons, besides the great relative size of the teeth, do you think it is
convenient to create a new taxon? I know it could be better to wait until
more material is available, but we have the Danish case: _Dromaeosauroides
bornholmensis_ (Christiansen and Bonde, Bonde and Christiansen or whatever),
a tooth taxon. And maybe this dromaeosaur (in view of Sereno's definition
I'm afraid to write "Dromaeosauridae" ) ocurrence is enough important for
its paleobiogeographical implications.

4) Is it possible to estimate the total lenght of the animal?
_D. bornholmensis_ lenght was estimated, for a 21 mm. high tooth, in more
than 3 metres.

Well, I hope you don't get bored with this piece. Merry X'mas to all of you!
Many thanks in advance,


Matías Soto
Departamento de Paleontología
Facultad de Ciencias
Montevideo, Uruguay